Risk Management and Fair Values (Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income) (Details) - Not Designated As Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Competitive Businesses Operating Revenues [Member] | Electricity Swaps And Options [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	$ 0.0	$ 0.0
Amount of gain (loss) recorded in income	5.0	1.0
Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	0.0	0.0
Amount of gain (loss) recorded in income	(1.0)	0.0
Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recognized in AOCI	0.0	0.0
Amount of gain (loss) recorded in income	21.0	32.0
Entergy Arkansas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	8.4	8.0
Entergy Louisiana [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	0.8
Entergy Louisiana [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	8.8	17.6
Entergy Mississippi [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	(1.8)	(0.2)
Entergy Mississippi [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	1.1	7.8
Entergy New Orleans [Member] | Fuel, Fuel Related Expenses And Gas Purchased For Resale [Member] | Natural Gas Swaps [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	0.2	(0.1)
Entergy New Orleans [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	1.9	3.3
Entergy Texas [Member] | Purchased Power Expense [Member] | Fixed Transmission Rights (FTRs) [Member]
Effect Of Derivative Instruments Not Designated As Hedging Instruments On The Consolidated Statements Of Income [Line Items]
Amount of gain (loss) recorded in income	$ 0.3	$ (3.5)